TW201919087A - Charged particle beam device, charged particle beam influencing device, and method of operating a charged particle beam device - Google Patents

Abstract

A charged particle beam device (100) is described, which includes: a beam source (110) configured to generate a charged particle beam (105) propagating along an optical axis (A); an aperture device (120) with a first number of apertures (125) configured to create a first number of beamlets (135) from the charged particle beam (105), wherein the first number is five or more, wherein the apertures (125) are arranged on a ring line (126) around the optical axis (A) such that perpendiculars (128) of the apertures (125) onto a tangent (136) of the ring line (126) are evenly spaced. The charged particle beam device (100) further includes an electrostatic multipole device configured to individually influence the beamlets. Further, a charged particle beam influencing device and a method of operating a charged particle beam device are described.

Description

Charged particle beam device, charged particle beam dominating device and method for operating charged particle beam device

Embodiments described herein relate to charged particle beam devices, and in particular to scanning electron microscopes configured to inspect samples, such as wafers or other substrates, for example, to detect pattern defects. More particularly, embodiments described herein relate to charged particle beam devices configured to utilize multiple charged particle beams (eg, electron beams), particularly for inspection system applications, test system applications, defect inspection, or critical dimensions Label applications, surface imaging applications, and more. Embodiments further relate to a charged particle beam dominating device and to a method of operating a charged particle beam device.

Modern semiconductor technology has created a high demand for structuring and profiling samples at the nanometer or even sub-nanometer level. Micron and nanoscale process control, inspection or structuring is typically accomplished with a charged particle beam (eg, an electron beam) that is generated, shaped, deflected, and focused in a charged particle beam device, such as an electron microscope. For inspection purposes, charged particle beams provide superior spatial resolution compared to, for example, photon beams because their wavelengths are shorter than the wavelength of the beam.

Inspection devices using charged particle beams, such as scanning electron microscopes (SEMs), have many functions in many industrial fields, including but not limited to inspection electronic circuits, exposure systems for lithography, detection devices, and defect detection tools. And test systems for integrated circuits. In such charged particle beam systems, fine profiling with high current densities can be used. For example, in the case of SEM, a primary electron (PE) beam produces signal particles, such as secondary electrons (SE) and/or backscattered electrons (BSE), that can be used to image and analyze the sample.

One disadvantage of electron beam based systems is the limited probe current within the focus. As the resolution increases (the dot size decreases), the probe current is further reduced due to the decrease in the aperture angle for controlling the aberration. Due to the electron-electron interaction, higher brightness sources can only provide limited improvements in the probe current. A number of approaches have been taken to reduce e-e interactions in electron beam systems, for example, reducing the column length and/or increasing column energy in conjunction with late deceleration of the electron beam for the final landing energy just prior to reaching the sample. However, increasing the amount of electron beam delivery at high resolutions is becoming more and more challenging.

One way to solve these problems is to use multiple bundles (also referred to herein as small bundles) in a single column. However, it is challenging to orient, scan, deflect, shape, correct, and/or focus individual beamlets of a multi-beam system, especially when the sample structure will be transported at high resolution in nanometer resolution. The amount to scan and check.

Accordingly, it would be beneficial to provide a charged particle beam device that is configured as a multi-beam system that provides high throughput and good field quality for inspection of the sample structure. In particular, it would be beneficial to provide a charged particle beam device capable of increasing the data collection rate, making the device applicable to high speed wafer inspection.

In view of the above, according to the independent request item, a charged particle beam device, a charged particle beam dominating device, and a method of operating a charged particle beam device are provided. Further aspects, advantages, and features of the embodiments are apparent from the scope of the claims, the description, and the accompanying drawings.

According to one aspect described herein, a charged particle beam device is provided. A charged particle beam apparatus includes: a beam source configured to generate a charged particle beam propagating along an optical axis; an aperture device having a first number of apertures configured to form a first number of beamlets from the charged particle beam, wherein One number is 5 or more, and wherein the apertures are disposed on the loop line about the optical axis such that the perpendiculars of the apertures projected on the tangent to the loop are evenly spaced apart; and the electrostatic multipole arrangement is configured to individually dictate the beamlets.

According to another aspect of the invention, a scanning electron microscope (SEM) for imaging a sample is provided. A scanning electron microscope includes: a beam source configured to generate a beam of primary particles propagating along an optical axis; an aperture device having a first number of apertures configured to form a first number of beamlets from the charged particle beam; Means, configured to individually administer the beamlets; and scanning means configured to scan the beamlets across the sample along the uniformly spaced scan lines in the first scan direction. The aperture of the aperture device is arranged on the loop along the optical axis.

According to another aspect described herein, a charged particle beam dominating device is provided. The charged particle beam dominating device includes: an aperture device having a first number of apertures configured to form a first number of beamlets from a beam of charged particles propagating along an optical axis, wherein the first number is 5 or greater and the aperture Arranged on the loop line about the optical axis such that the perpendiculars of the apertures projected on the tangent to the loop are evenly spaced apart; and the electrostatic multipole arrangement, integrated with the aperture means, and configured to individually administer the beamlets.

According to another aspect described herein, a method of operating a charged particle beam device is provided. The method includes: generating a beam of charged particles propagating along an optical axis; directing a beam of charged particles through a first number of apertures disposed on a loop along an optical axis to form a first number of beamlets, wherein the first number is 5 or more The beamlets are individually administered; and the beamlets are moved relative to the sample in a first scanning direction along uniformly spaced scan lines.

Embodiments are also directed to apparatus for performing the disclosed methods and include apparatus parts for performing separate method actions. These methods may be performed by means of hardware components, a computer programmed by a suitable software, any combination of the two or in any other manner. Furthermore, embodiments are directed to methods of operating the described devices.

Additional advantages, features, and details that may be combined with the embodiments described herein are apparent from the dependent claims, the description and the drawings.

Reference will now be made in detail to the various embodiments of the invention In the following description of the drawings, the same component symbols refer to the same components. In general, only the differences with respect to individual implementations are described. Each example is provided by way of explanation and is not meant to be limiting. In addition, features illustrated or described as part of one embodiment can be used in other embodiments or in combination with other embodiments to produce a further embodiment. This description is intended to cover such modifications and variations.

Semiconductor technology relies on accurate control of the various processes used during the production of integrated circuits. For example, substrates such as wafers and masks must be repeatedly inspected to locate problems or defects. The mask or mask must be inspected prior to actual use during substrate processing to ensure that the mask accurately defines the predetermined pattern. Any defects in the mask pattern will be transferred to the substrate during use in microlithography. Inspecting defects of a sample, such as a substrate, wafer or mask, typically involves inspecting large areas in a relatively short period of time. Inspection should be as fast as possible in order to avoid production production being reduced by the inspection process.

Scanning electron microscopy (SEM) can be used to inspect samples to detect defects such as pattern defects. A sample of charged particles (eg, an electron beam) that can be focused on the surface of the sample is used to scan the surface of the sample. Secondary charged particles (eg, secondary electrons) are generated and detected as the charged particle beam strikes the sample. A pattern defect at that location of the sample can be detected by comparing the intensity signal of the secondary charged particle to a reference signal, for example, corresponding to the same location of the sample. When only one charged particle beam is used for scanning, the scanning may take a considerable amount of time and only a limited amount of delivery may be obtained.

The amount of delivery can be increased by providing a charged particle beam device that is configured as a multi-beam system. In a multi-beam system, a plurality of charged particle beamlets are generated that propagate in the column close to each other such that two or more points on the sample can be simultaneously examined. However, it is challenging to control, shape, and correct multiple beamlets that propagate in close proximity relative to each other in one column. In accordance with embodiments described herein, a charged particle beam device 100 is provided that provides both high throughput and high inspection accuracy.

1 is a schematic cross-sectional view of a charged particle beam device 100 configured as a multi-beam system, in accordance with an embodiment described herein.

The charged particle beam device 100 includes a beam source 110 that is configured to generate a charged particle beam 105 that propagates along an optical axis A. Beam source 110 can be an electron source configured to generate an electron beam. The charged particle beam 105 can travel from the beam source 110 through the column toward the sample 10 along the optical axis, and the optical axis can be at the center of the column. A plurality of beam dominating elements may be arranged along the beam path between the beam source and the sample, such as one or more deflectors, beam correctors, lens devices, apertures, beam benders, and/or beam splitters (not shown in Figure 1 show).

In some embodiments, beam source 110 can include at least one of a cold field emitter (CFE), a Schottky emitter, a TFE, or another high current electron beam source, for example to increase throughput. The high current is considered to be 10 μA or higher at 100 Mrad, for example, up to 5 mA, for example, 30 μA at 100 Mrad to 1 mA at 100 Mrad. According to a typical implementation, the current is substantially evenly distributed, for example, the deviation is + -10%. According to some embodiments, which may be combined with other embodiments described herein, the source may have a diameter of 2 nm to 40 nm and/or a typical emission half with 5 Mrad or higher, for example, 50 Mrad Up to 200 millirads.

According to embodiments that can be combined with other embodiments described herein, the TFE or another high brightness reduction source capable of providing a large beam current (eg, an electron beam source) is 20 that does not decrease in brightness when the emission angle increases. % source to provide a maximum of 10μA-100μA, for example 30μA. Schottky or TFE emitters are currently available with a measured reduced brightness of 5 x 10 ⁷ Am ^-2 (SR) ^-1 V ^-1 and CFE emitters with up to 5 x 10 ⁹ Am ^-2 (SR ) ^-1 V ^-1 measures the reduced brightness. The system can also work with the carbide emitter (such as HfC), which may have about ^{1 × 10 11 Am -2 (SR} ) ^-1 V ^-1 to reduce the luminance. For example, a bundle having at least 5 x 10 ⁷ Am ^-2 (SR) ^-1 V ^-1 is beneficial.

The charged particle beam device 100 further includes an aperture device 120 having a first number of apertures 125 configured to form a first number of beamlets 135 from the charged particle beam 105, wherein the first number is 5 or more. In other words, aperture device 120 includes five or more apertures configured to form five or more beamlets. In other embodiments, the aperture device 120 can have eight or more apertures configured to form eight or more beamlets. Each aperture of aperture device 120 can be configured to form a beam of charged particles from a beam of charged particles.

The aperture device 120 can include a substrate, such as a flat plate, wherein the aperture 125 is formed as an opening or hole in the substrate. When the charged particle beam 105 impinges on the substrate in which the aperture 125 is formed, the charged particles may propagate through the aperture 125 in the substrate to form the beamlet 135, and the remaining portion of the charged particle beam 105 may be blocked by the substrate. At least one surface of the aperture device 120, for example, the surface of the aperture device 120 directed to the beam source 110 can be a conductor or semiconductor surface to reduce or avoid charge buildup on the aperture device 120.

Figure 2 shows the aperture device 120 in more detail in a bottom view (i.e., from the perspective of the sample 10). As shown in FIG. 2, five or more apertures of the aperture device are disposed on the loop 126 about the optical axis A. Loop 126 is typically, but not necessarily, a circular line. Thus, five or more beamlets produced by directing charged particle beam 105 through aperture device 120 may have substantially the same distance from optical axis A. Producing a beamlet such that the beamlets have the same distance from the optical axis A can have the advantage that the dominating beamlets result in similar aberrations for the individual beamlets, so similar aberrations of the individual beamlets can be corrected more easily. Additionally, the beamlets 135 can be focused onto the sample 10 by focusing a single objective lens of each beamlet in a corresponding manner.

In the cross-sectional view of Figure 1, only two of the five or more beamlets are depicted. For example, the cross-sectional view of FIG. 1 can be taken along a cross-sectional plane C indicated as a dashed line in FIG. Thus, the two apertures shown in FIG. 1 may correspond to the first aperture 121 and the second aperture 122 of the aperture device 120 of FIG. 2, with the two apertures being on opposite sides of the loop 126. The remaining three or more beamlets formed by aperture device 120 are not shown in FIG.

The aperture 125 is disposed about the optical axis A on the loop 126 such that the perpendiculars 128 of the aperture 125 projected onto the tangent 136 of the loop 126 are evenly spaced apart. "Vertical line of aperture" can be understood as the line of connection between the center of the aperture and the tangent 136, wherein the line is perpendicular to the tangent 136. The vertical lines 128 are parallel to each other, and each vertical line is perpendicular to the common tangent line. The distance D1 between two adjacent vertical lines 128 is substantially equal, respectively.

Thus, the beamlet 135 can be scanned over the sample along the first number of uniformly spaced scan lines in the first scan direction X (corresponding to the direction of the perpendicular 128 in FIG. 1).

It is to be noted that the direction of the vertical line 128 does not necessarily correspond to the first scanning direction X. For example, the beamlets 135 can be co-rotated about the optical axis by magnetic lens elements that can be disposed between the aperture device 120 and the sample 10. The common rotation about the optical axis A maintains the relative distance between the beamlets such that the beamlets are evenly spaced apart in the (rotation) projection after rotation.

In accordance with embodiments described herein, a multi-beam system is provided in which the beamlets are located on the loop line about the optical axis A. The optical axis A can correspond to the center of the column. Although the first number of beamlets arranged on the loop is five or more, the beamlets are evenly spaced apart in the projection such that the beamlets can be scanned along the substantially equidistant direction in the first scanning direction X The line is scanned.

It is noted that when five or more apertures are not disposed on the loop line 126 at evenly spaced angular positions relative to the optical axis, the five or more beamlets may only be evenly spaced apart in the projection. In the example depicted in Figure 2, some of the adjacent apertures define an angle of 90 with respect to the center of the aperture device, while other adjacent apertures define an angle of 45°. However, in projection, the distance D1 between the generated beamlets is substantially equal. Similarly, in the example depicted in FIG. 4, in the case where the first number is 8 (ie, eight apertures for forming eight beamlets), the apertures are arranged at angular positions that are not evenly spaced, It is possible to scan small beams along evenly spaced scan lines during projection.

When the beamlets are scanned along unevenly spaced scan lines, there is a loss in throughput because at some point, areas scanned by some closely packed beams may overlap while other bands may remain unscanned. This causes a loss of throughput because some of the small bundles may be idle during the time of scanning the unscanned area.

On the other hand, according to embodiments described herein, the beamlets can be scanned along uniformly spaced scan lines (ie, along equally spaced scan lines). The increase can be achieved, for example, by first scanning the beamlets along the uniformly spaced scan lines in the first scanning direction X, and then moving the beamlets in the second lateral scanning direction until the predetermined area of the sample is completely scanned. The amount of delivery. Some beam line idle time can be reduced or completely avoided. Thereafter, the sample can be moved or displaced, whereby another region of the sample can be raster scanned.

According to some embodiments, the charged particle beam device can include a scanning device configured to scan the beamlets 135 through the sample 10 in a first scanning direction X along uniformly spaced scan lines. Optionally, the scanning device can be configured to deflect the beamlet 135 in a second lateral scanning direction, the second lateral scanning direction being perpendicular to the first scanning direction X.

The charged particle beam device 100 further includes an electrostatic multipole device 150 that is configured to individually administer the beamlets 135. In some embodiments, the electrostatic multipole device 150 is disposed downstream of the aperture device 120 and includes a plurality of electrostatic multipoles 151 that are configured to individually dictate the beamlets 135, ie, each beamlet It can be dominated by the associated electrostatic multipole.

As used herein, "dominated beamlet" is understood to mean at least one or more of deflection, shaping, correction, focusing, and/or collimation of the beamlets. For example, the electrostatic multipole device 150 can include a plurality of electrostatic deflector units, wherein each deflector unit can be configured to deflect one of the beamlets 135. For example, an electrostatic multipole device can include a plurality of electrostatic quadrupoles or octapoles, wherein each electrostatic quadrupole or octupole can be configured to correct for aberrations of one of the beamlets 135.

The electrostatic multipole device can be configured to individually dictate each beamlet. For example, an electrostatic multipole device can have a first number of electrostatic multipoles, wherein each electrostatic multipole is associated with one of a first number of beamlets such that the individual can be individually dictated via an associated electrostatic multipole Small bunch. In particular, each beamlet can be dominated by the associated electrostatic multipole of the electrostatic multipole device independently of the other beamlets. In some embodiments, the electrostatic multipole device 150 can have a first number of electrostatic multipoles 151 corresponding to a first number of beamlets such that each beamlet can be dominated independently of other beamlets, where the first number is 5 or more.

The electrostatic multipole device 150 is disposed downstream of the aperture device 120. For example, the electrostatic multipole device 150 can be disposed directly downstream of the aperture device, i.e., there is no other dominating unit between the aperture device and the electrostatic multipole device, as exemplarily depicted in FIG. In some embodiments, the electrostatic multi-pole device 150 can be integrated with the aperture device 120, as exemplarily depicted in FIG.

It is beneficial to provide the electrostatic multipole device 150 downstream of the aperture device 120 because the beamlets can be deflected, focused, and/or corrected after being formed by the aperture device such that the beamlets propagate accurately toward a predetermined point on the sample. In the case where the angular distance between adjacent beamlets is not equal, it is particularly advantageous to separately administer the beamlets after forming the beamlets. This is because collectively tying all of the beamlets with a single electrostatic field can provide reduced deflection accuracy and/or correction accuracy than if the beamlets are individually dominated. Therefore, the amount of conveyance can be further increased by separately controlling the small bundle. Additionally, the electrostatic multi-pole device 150 configured to individually administer the beamlets provides increased adjustment and flexibility options such that the beam path and beam shape can be corrected and adjusted more easily and accurately.

In some embodiments, the electrostatic multipole 151 of the electrostatic multipole device 150 can be configured as an electrostatic dipole, quadrupole, hexapole, or octupole. The electrostatic multipole device 150 can include an associated electrostatic dipole, quadrupole, hexapole or octupole for each beamlet 135.

The electrostatic dipole comprises two electrodes for dosing a small beam of charged particles, wherein two electrodes may be arranged on opposite sides of the beamlet. The electrostatic dipole can be used to deflect the beamlets in one direction perpendicular to the direction of beam propagation.

The electrostatic quadrupole includes four electrodes for dosing a beam of charged particles, four of which may be arranged at equiangular locations around the beamlets. The electrostatic quadrupole can be used to deflect the beamlets in two directions perpendicular to the beam propagation direction and/or to correct beam aberrations.

The electrostatic eight poles comprise eight electrodes for dosing a small beam of charged particles, eight of which may be arranged at equiangular locations around the beamlets. Electrostatic eight poles can be used to deflect beamlets in various directions and/or to correct beam aberrations. It is possible to correct higher order aberrations than the electrostatic quadrupole.

It is noted that electrostatic multipoles can also be used for beam focusing and/or defocusing (eg, by applying a corresponding potential to the electrodes of the electrostatic multipole).

In some embodiments, the electrostatic multipole 151 of the electrostatic multipole device 150 includes two, four, six, eight or more electrodes that are each evenly spaced relative to the center of the associated aperture. The angular position is arranged downstream of the associated aperture. The electrostatic multipole 151 can be configured to individually deflect, correct, shape, and/or focus at least one of an associated beamlet, respectively.

As shown in FIG. 2, the distance D1 between two adjacent vertical lines 128 may substantially correspond to the maximum diameter of the loop line 126 divided by the number of apertures minus one. For example, when the first number is 5, the distance D1 between two adjacent vertical lines 128 may correspond to a quarter of the diameter of the loop line 126, as schematically depicted in FIG. This aperture arrangement on the loop 126 is beneficial because large areas (e.g., wide strips) on the sample can be scanned prior to sample displacement.

In some embodiments, a scanning device can be provided, the scanning device being configured to scan the beamlets across the sample along the uniformly spaced scan lines in the first scanning direction X. The first scanning direction X is typically set according to the direction of the vertical line. For example, the scanning device can be configured to scan the beamlet raster over the sample by alternately scanning along the uniformly spaced scan lines in the first scan direction X and moving the beamlets in the second lateral scan direction. The second lateral scanning direction may be perpendicular to the first scanning direction. This sequence can be repeated until the sample strip having a width equal to or greater than the diameter of the loop 126 has been completely scanned. Thereafter, the sample can be displaced to another location, for example, by a distance corresponding to the width of the previously scanned strip.

In some embodiments, which can be combined with other embodiments described herein, the electrostatic multipole device 150 can be configured to deflect the beamlets 135 such that each beamlet appears to be from a different source. For example, electrostatic multipole device 150 can include a separate deflector for each beamlet, as depicted schematically in FIG. In particular, the individual deflectors may comprise electrostatic multipoles, such as electrostatic dipoles, quadrupoles, hexapoles or octupoles. It may be beneficial to provide an electrostatic multipole device 150 having a plurality of electrostatic quadrupoles or octapoles because the electrostatic quadrupole or octupole can be used for focusing, deflecting, and correcting.

FIG. 3 is a schematic cross-sectional view of a charged particle beam device 200 in accordance with an embodiment described herein. The charged particle beam device 200 of FIG. 3 may include most of the features of the charged particle beam device 100 of FIG. 1 such that reference may be made to the above description without being repeated here.

The charged particle beam device 200 includes a beam source 110 for generating a charged particle beam 105 that travels from the beam source 110 through the column to the sample 10 to be inspected. The charged particle beam device 200 further includes a charged particle beam dominating device 210.

Figure 4 shows the charged particle beam dominating device 210 (i.e., from the perspective of the sample 10) in more detail in a bottom view. The charged particle beam dominating device 210 includes an aperture device 220 and an electrostatic multipole device 250 that can be integrally formed. In other words, the aperture device 220 and the electrostatic multipole device 250 may be integrally formed as a single component, that is, may be connected or fixed to each other, or may be formed of a single multilayer substrate.

In some embodiments, which may be combined with other embodiments described herein, aperture device 220 includes a substrate 221 that includes an insulator layer on which an electrostatic multipole 151 of electrostatic multipole device 250 is formed.

A first number of apertures 125 are formed in the substrate 221 of the aperture device 220, wherein the first number is 5 or more. In the embodiment of Figure 4, the first number is eight. The aperture 125 is configured to form a first number of beamlets 135 from the charged particle beam 105. Thus, the aperture device 220 of Figure 4 is configured to form eight beamlets. In other embodiments, the first amount can be greater than 8, for example, 10 or more.

As shown in FIG. 4, the apertures 125 are disposed about the optical axis A on the loop 126 such that the perpendiculars 128 of the apertures 125 projected onto the tangent 136 of the loop 126 are evenly spaced apart. Therefore, the distance D2 between adjacent beamlets in the projection is similar or identical, respectively. The distance D2 may generally correspond to the diameter of the loop 126 divided by 7 (8 minus 1).

Therefore, it is possible to scan the small beam 135 through the sample 10 along the uniformly spaced or equidistant scan lines in the first scanning direction X. Reference will be made to the above description and will not be repeated here.

The electrostatic multipole 151 of the electrostatic multipole device 250 may be disposed on a surface of the substrate 221 that is directed downstream (ie, toward the sample 10). Thus, a beamlet formed by propagating through one of the apertures can be dominated immediately after formation, for example, by an associated electrostatic multipole that can be formed on the substrate 221 to deflect, correct, and/or focus.

As shown in detail in FIG. 4, the electrostatic multi-pole device 250 can include a first number of electrostatic multipoles 151 corresponding to a first number of apertures 125, ie, eight electrostatic multipoles, such as quadrupole or octapole. . In the exemplary embodiment of FIG. 4, the electrostatic multipole 151 is configured as a quadrupole.

The electrostatic multipole 151 may include four or more electrodes, and four or more electrodes may be formed on one main surface of the substrate 221 around one aperture for tying a small beam after propagating through the aperture. In some embodiments, each of the four or more electrodes can be disposed at the same distance from the center of the aperture. In some embodiments, each of the four or more electrodes can be disposed at a radial distance from the beam limiting edge of the aperture. For example, as schematically depicted in FIG. 4, the electrode 152 is disposed at a radial distance from the beam limiting edge 153 of the first aperture 121. In other words, the electrode 152 itself does not form a beam limiting edge for the beamlet, but the electrode 152 is disposed radially outward with respect to the beam limiting edge 153 of the first aperture 121. Therefore, the beamlets do not propagate through the edge regions of the electric field of the electrostatic multipole, and the electric field in the edge regions may deviate from the electric field in the central region of the aperture. The beam limiting edge 153 of the aperture limits the radial extension of the beamlets that propagate through the aperture.

According to some embodiments, which can be combined with other embodiments described herein, the charged particle beam dominating device 210 includes a substrate 221 configured to provide an aperture 125 for forming a beamlet and for carrying an electrostatic multipole device downstream of the aperture Electrode.

The electrodes of the electrostatic multipole 151 may be disposed at equally spaced angular positions on the surface of the substrate 221 with respect to one of the apertures. The substrate 221 may be a flat substrate, such as a wafer, such as a multilayer wafer. For example, the substrate 221 may be a multilayer wafer having at least one insulator layer on which electrodes are formed.

In some embodiments, which may be combined with other embodiments disclosed herein, the aperture may have a circular or circular cross-sectional shape. Thus, by directing the wide-angle charged particle beam through the aperture, a round or circular beam of charged particles can be produced. The pore size may have a diameter of 1 mm or less, in particular 500 μm or less, more particularly 200 μm or less, or even 100 μm or less.

The fabrication of the charged particle beam dominating device 210 in accordance with embodiments disclosed herein may be simplified when some or all of the electrodes of the electrostatic multipole 151 include tantalum or doped germanium. The ruthenium electrode disposed on the top of the flat substrate can be formed in a miniaturized form from the SOI substrate (on-insulator) in a particularly easy manner. The conductivity of the crystalline germanium or doped germanium may be sufficient to form an electrostatic multipole electrode therefrom. In other implementations, the electrodes of the electrostatic multipole 151 can comprise a metal. Additionally, other material systems may be suitable for providing a multi-layer wafer structure having an insulator layer and a semiconductor layer similar to an SOI wafer.

The electrodes of the electrostatic multipole 151 can be configured to be connectable to respective potentials. For example, a voltage source can be provided to connect each electrode to a corresponding voltage. In some cases, each electrode can be coupled to a respective connection line to connect the electrode to a voltage source. The connecting wires can be at least partially integrated in the insulator layer of the substrate. In some embodiments, the connection lines can be provided at least partially on the surface of the substrate 221. For example, the connecting line for connecting the electrodes to the respective potentials can be made of the same material as the electrodes.

In some embodiments, the substrate can include an insulator layer 222, an electrode is formed on top of the insulator layer, and the substrate can include an additional layer 223 on an opposite side of the insulator layer 222 with respect to the side on which the electrode is formed, an additional layer Includes semiconductor or conductor materials (see Figure 6). The additional layer 223 can be directed to the upstream side of the charged particle beam dominating device 210. The additional layer 223 can be made of a metal or a semiconductor, in particular tantalum. In some implementations, both the electrode and the additional layer 223 can be made of tantalum, while the insulator layer 222 can comprise SiO ₂ or another insulator, such as sapphire. The accumulation of charge on the surface of the substrate can be reduced or avoided. For example, an additional layer 223 can be connected to a potential, such as a ground potential.

The electrodes can be formed on the substrate 221 by applying a mask on the multilayer substrate and removing portions of the initially uniform top layer such that the remaining portion of the top layer forms an electrode.

The electrodes may comprise or consist of ruthenium. To fabricate the electrode, an initial uniform layer of germanium, which may be the top layer of the SOI wafer, may be partially removed (eg, etched) such that the remaining portion of the germanium layer forms an electrode. The electrodes may be substantially trapezoidal and may be arranged around the aperture at evenly spaced angular positions, as shown in FIG. In some embodiments, which may be combined with other embodiments described herein, the electrodes may each extend around an angle of less than 30°, particularly less than 15°, around one of the apertures.

FIG. 5 is a schematic cross-sectional view of a charged particle beam device 100 in accordance with an embodiment described herein. The charged particle beam device 100 can include a beam source 110, an aperture device 120, and an electrostatic multipole device 150 similar to the embodiment shown in FIG. 1, such that reference can be made to the above description without being repeated here.

Charged particle beam 105 is generated by beam source 110 and directed through aperture device 120. The aperture device 120 is configured to form a first number of beamlets 135 from the charged particle beam. The first number is 5 or more, but only two beamlets 135 are shown in the cross-sectional view of FIG. The beamlets 135 propagate through the electrostatic multipole device 150. Each beamlet 135 can propagate through an associated static multipole 151 of the electrostatic multipole device 150 that is configured to individually dictate the beamlets.

For example, the beamlets 135 can be deflected by an electrostatic multipole device such that each beamlet appears to be from a different source. Alternatively or additionally, the beam aberration of the beamlets can be corrected by applying a suitable electrostatic multipole field.

The beamlets can optionally propagate through a beam splitter device 195 that is configured to separate secondary electrons and/or backscattered electrons generated at the location of the sample from the beamlets 135.

Scanning device 140 may be provided to scan beamlet 135 over sample 10 in a first scan direction X and/or in a second lateral scan direction that may be perpendicular to first scan direction X. The first scanning direction X may be perpendicular to the cross-sectional plane of FIG. Five or more small beams may be scanned along an equidistant scan line extending in the first scanning direction X.

The charged particle beam device 100 can further include an objective lens 190 configured to focus the beamlet 135 onto the sample 10. The objective lens 190 may be a combined magnetic-electrostatic objective lens including a magnetic lens portion and an electrostatic lens portion.

The electrostatic portion of the composite magnetic-electrostatic lens can be an electrostatic hysteresis lens. The use of such a composite magnetic-electrostatic lens produces excellent resolution at low landing energies, for example, a few hundred electron volts in the case of SEM. This low landing energy is beneficial to avoid charging and/or damage to radiation sensitive samples, especially in the modern semiconductor industry. However, in some cases, only a magnetic lens or only an electrostatic lens may be used.

The objective lens 190 can not only focus the beamlets, but also rotate the beamlets around the optical axis. This effect is not shown because it is difficult to draw in a two-dimensional schema and because the skilled person is well aware of this effect. Due to the combined effect of the electrostatic multipole device and the objective lens, a plurality of dots are formed on the sample, each dot corresponding to a small beam.

When the beamlets hit the surface of the sample 10, the beamlets undergo a series of complex interactions with the nuclei and electrons of the atoms of the sample. The interaction produces various secondary products such as electrons of different energies, X-rays, heat and light. Many of these secondary products are used to generate sample images and collect other data. The secondary product that is important for the inspection or imaging of the sample is the secondary electron, which escapes from the sample at various angles with relatively low energy (1 to 50 eV). The signal electrons are extracted from the sample through the objective lens, separated from the primary beam, and reach the detector device.

Thus, the first number of beamlets 135 interact with the sample 10 at a first number of points such that a plurality of beamlets of secondary or backscattered electrons are emitted from the sample 10.

The sample 10 can be held on a movable stage 11 that is configured to move the sample in at least one direction (eg, in a direction perpendicular to the first scanning direction X). In some embodiments, the mobile station 11 can be configured to move samples in two or more directions.

In some embodiments, a beam splitter device 195 can be provided to separate multiple beamlets of secondary or backscattered electrons from a first number of beamlets 135. A beam of secondary or backscattered electrons can be directed to the detector device 180.

In some embodiments, a detector device 180 can be provided that is configured to detect secondary charged particles and/or backscattered charged particles emitted from the sample 10. The detector device 180 can be subdivided into a plurality of segments that are configured to detect secondary or backscattered electrons generated by one of the beamlets 135, respectively. For example, the detector device 180 depicted in FIG. 5 includes a first detector segment 181 and a second detector segment 182, the first detector segment being configured to detect a secondary charging generated by the first beamlet The second detector segment is configured to detect secondary charged particles generated by the second beamlet. Additional detector segments can be provided. The number of detector segments may correspond to a first number such that each beamlet has an associated detector segment.

FIG. 6 is a schematic cross-sectional view of a charged particle beam device 200 in accordance with an embodiment described herein. The charged particle beam device 200 substantially corresponds to the charged particle beam device 100 shown in Fig. 5, so that the above description can be referred to without repeating here. However, instead of spatially separated aperture devices and electrostatic multipole devices, a charged particle beam dominating device 210 as depicted in FIG. 4 can be provided.

The charged particle beam dominating device 210 includes: an aperture device 220 having a first number of apertures configured to form a first number of beamlets 135 from the charged particle beam 105; and an electrostatic multipole device 250, the electrostatic multipole The device is integrally formed with the aperture device 220. The electrostatic multi-pole device 250 includes a plurality of electrostatic multipoles 151 that are configured to individually administer the beamlets 135.

The apertures 125 are arranged on the loop along the optical axis A such that the perpendiculars of the apertures projected onto the tangent to the loop are evenly spaced apart. Therefore, the beamlets can be scanned along the equidistant scan lines in the first scanning direction X.

The charged particle beam dominating device 210 may include a substrate having an insulator layer 222 and an additional layer 223 on which electrodes of the electrostatic multipole 151 are formed, and the other layer may be a conductor or a semiconductor layer. The aperture 125 can be formed in the substrate, for example, in an etching process.

7 is a flow chart showing a method of operating a charged particle beam device, in accordance with an embodiment described herein.

In block 710, a charged particle beam, in particular an electron beam, is formed, the charged particle beam propagating along the optical axis A.

In block 720, a first number of beamlets are formed by directing the charged particle beam through a first number of apertures disposed about the optical axis on the loop, wherein the first number is 5 or more.

In block 730, the beamlets are individually governed, for example, individually deflected, corrected, focused, and/or shaped. For example, each beamlet may be subject to the associated electrostatic multipole of the electrostatic multipole device.

The beamlets can be deflected by an electrostatic multipole device. Additionally or alternatively, the beam aberrations of the beamlets may be corrected by an electrostatic multipole device.

In block 740, the beamlets are moved relative to the sample in a first scan direction X along uniformly spaced scan lines.

The sample may be raster scanned by moving the beamlets across the sample along the equidistant scan line in the first scan direction and in the second lateral scan direction. The second lateral scanning direction may be perpendicular to the first scanning direction. Raster scanning in the first scanning direction X and in the second lateral scanning direction may be repeated until a predetermined area of the sample has been scanned. Thereafter, the sample can be moved, for example, by a mobile station.

In block 750, the method can further include detecting secondary and/or backscattered charged particles emitted by the sample, particularly wherein the secondary and/or backscattered charged particles produced by each beamlet are segmented by segmentation A section of the detector device is separately detected.

While the foregoing is directed to a particular embodiment, the invention may be inferred in the scope of the invention, and the scope of the invention is determined by the scope of the appended claims.

10‧‧‧ sample

11‧‧‧Removable station

100‧‧‧ charged particle beam device

105‧‧‧Charged particle beam

110‧‧‧ Beam source

120‧‧‧Aperture device

121‧‧‧First aperture

122‧‧‧second aperture

125‧‧‧ aperture

126‧‧‧Circle

128‧‧‧ vertical line

135‧‧‧Small bundle

136‧‧ tangential

140‧‧‧Scanning device

150‧‧‧Electrostatic multipole device

151‧‧‧Electrostatic multipole

152‧‧‧electrode

153‧‧‧Limited edge

180‧‧‧Detector device

181‧‧‧First detector segment

182‧‧‧Second detector segment

190‧‧‧ Objective lens

195‧‧‧Bundle separator device

200‧‧‧ charged particle beam device

210‧‧‧Charged particle beam dominating device

220‧‧‧Aperture device

221‧‧‧ board

222‧‧‧Insulator layer

223‧‧‧Additional layers

250‧‧‧Electrostatic multipole device

710-750‧‧‧ box

Therefore, in order to enable a detailed understanding of the manner in which the above-described features of the embodiments are used, a more specific description of the embodiments briefly outlined above may be made with reference to the embodiments. One or more embodiments are described with reference to the drawings and are described as follows:

1 is a schematic cross-sectional view of a charged particle beam device in accordance with an embodiment described herein;

2 is a schematic bottom view of an aperture device of a charged particle beam device in accordance with embodiments described herein;

3 is a schematic cross-sectional view of a charged particle beam device in accordance with an embodiment described herein;

4 is a schematic bottom view of a charged particle beam dominating device in accordance with embodiments described herein;

Figure 5 is a schematic illustration of a charged particle beam device in accordance with embodiments described herein;

Figure 6 is a schematic illustration of a charged particle beam device in accordance with embodiments described herein;

7 is a flow chart showing a method of operating a charged particle beam device, in accordance with an embodiment described herein.

Domestic deposit information (please note according to the order of the depository, date, number)

Foreign deposit information (please note in the order of country, organization, date, number)

Claims (20)

A charged particle beam apparatus (100) comprising: a beam source (110) configured to generate a charged particle beam (105) propagating along an optical axis (A); having a first number of apertures (125) An aperture device (120, 220) configured to form a first number of beamlets (135) from the charged particle beam (105), wherein the first number is 5 or more, and wherein the aperture (125) Arranged around the optical axis (A) on a loop (126) such that the perpendicular (128) of the aperture (125) projected onto the line (136) of the loop (126) is evenly spaced; and An electrostatic multipole device (150, 250) is configured to individually administer the beamlet (135). The charged particle beam device of claim 1, wherein the electrostatic multipole device (250) and the aperture device (220) are integrally formed. The charged particle beam device of claim 1 or 2, wherein the aperture device (220) comprises a substrate (221) on which the electrostatic multipole of the electrostatic multipole device (250) is formed. The charged particle beam device of any one of claims 1 to 2, wherein the electrostatic multipole device (150, 250) comprises a plurality of electrostatic multipoles (151), the plurality of electrostatic multipoles being configured to be individually The first number of small bundles (135) are dominated. The charged particle beam device of claim 4, wherein the electrostatic multipole device comprises a plurality of dipoles, quadrupoles or octupoles. The charged particle beam device of claim 4, wherein the electrostatic multipole (151) comprises four disposed at a uniformly spaced angular position relative to a center of an associated aperture, respectively, downstream of the associated aperture , six, eight or more electrodes. The charged particle beam device of any one of claims 1 to 2, wherein a distance (D1, D2) between two adjacent perpendiculars (128) substantially corresponds to a diameter of the loop (126) Decrease by the first number by one. The charged particle beam device of any one of claims 1 to 2, further comprising: a scanning device (140) configured to scan along the evenly spaced intervals in a first scanning direction (X) The line scans the beamlet over the same (10). The charged particle beam device of claim 8, wherein the scanning device (140) is configured to alternately scan in the first scanning direction (X) along a uniformly spaced scan line and in a second The beamlet (135) is moved in the lateral scanning direction to scan the beamlet (135) raster through the sample (10). The charged particle beam device of any one of claims 1 to 2, wherein the electrostatic multipole device (150, 250) is configured to deflect the beamlet (135) such that each of the beamlets is viewed It comes from a different source. The charged particle beam device of claim 10, wherein the electrostatic multipole device (150, 250) includes a separate deflector for each of the beamlets. The charged particle beam apparatus of claim 11, wherein the individual deflector comprises a static multipole selected from the group consisting of: an electrostatic dipole, a quadrupole, a six pole, and an eight pole. The charged particle beam device of any one of claims 1 to 2, further comprising: an objective lens (190) configured to focus the beamlet (135) onto the same (10); and a detection The device (180) is configured to detect secondary charged particles and/or backscattered charged particles emitted from the sample (10). The charged particle beam device of claim 13, wherein the objective lens (190) is a combined magnetic-electrostatic objective lens comprising a magnetic lens portion and an electrostatic lens portion. A charged particle beam dominating device (210) comprising: an aperture device (220) having a first number of apertures (125) configured to form a charged particle beam propagating along an optical axis (A) a first number of beamlets (135), wherein the first number is 5 or greater, wherein the aperture (125) is disposed about the optical axis (A) on a loop (126) such that it is projected onto the loop (126) The perpendicular (128) of the aperture (125) on all lines (136) are evenly spaced apart; and an electrostatic multipole device (250) is integrated with the aperture device (220) and configured to The beamlets (135) are individually governed. A method of operating a charged particle beam apparatus, comprising the steps of: generating a charged particle beam (105) propagating along an optical axis (A); directing the charged particle beam to be disposed around a circular line (126) about the optical axis a first number of apertures (125) thereon to form a first number of beamlets (135), wherein the first number is 5 or more; separately dictate the beamlets; and along uniformly spaced scans The line moves the beamlet (135) relative to the same book (10) in a first scanning direction (X). The method of claim 16, further comprising the step of detecting secondary and/or backscattered charged particles emitted by the sample (10). The method of claim 16, wherein the secondary and/or backscattered charged particles generated by the beamlet (135) are detected by respective detector segments of a detector device (180). The method of any one of claims 16 to 18, comprising the step of: displacing the beamlet in the first scanning direction (X) and in a second scanning direction perpendicular to the first scanning direction (135) Moving the sample to raster scan the sample (10). The method of any of claims 16 to 18, wherein the step of separately tying the beamlet comprises the step of separately deflecting, focusing and correcting at least one of the beamlets.